JP2001300871A - Master arm device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control all degrees of freedom of a slave arm having degree 7 in a master slave manipulator by only a single arm of an operator by providing a master arm capable of reflecting not only the positional attitude of a hand of the operator but also the motion of an elbow. SOLUTION: In a master arm having freedom degree 7, a first rotary shaft 1, a second rotary shaft 2 and a third rotary shaft 3 on a shoulder part intersect with one another at an approximately single point, a fifth rotary shaft 5, a sixth rotary shaft 6 and a seventh rotary shaft 7 on a wrist part intersect with one another at an approximately single point, and a forth rotary shaft 4 is provided on an elbow part. An elbow sensor 11 for detecting the position of the elbow of an operator is provided near the elbow part, a driving device 14 for driving the elbow part is provided, the motion of the operator's elbow is detected, and the elbow part of the master arm is follow-controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a master arm having seven degrees of freedom used for a master-slave manipulator, and more particularly to a seven-degree-of-freedom master arm capable of controlling the position of an elbow of a slave arm.

[0002]

2. Description of the Related Art In a manipulator having six degrees of freedom,
When the position and posture of the hand are determined, all degrees of freedom are defined, and it is impossible to change the state of the arm between the shoulder and the hand. For this reason, obstacle avoidance and singularity avoidance cannot be performed in a state where the position and posture of the hand are determined. On the other hand, the human arm has seven degrees of freedom, and the position of the elbow can be arbitrarily selected even if the position and posture of the hand is determined, so that the arm does not hit even if there is an obstacle. Can be avoided. Therefore, by giving the slave arm of the master-slave manipulator seven degrees of freedom, it is possible to make use of redundant degrees of freedom to make it move in the same way as a human arm, and to avoid singularities and obstacles. can do.

[0003] The master arm in the master-slave manipulator is for manipulating the slave arm. When the operator moves the gripping portion at the tip of the master arm, the movement is transmitted as a command value and the same movement is given to the slave arm. Can be made. Conventionally, the master arm teaches six degrees of freedom of the position and posture of the hand held by the operator. To operate a seven-degree-of-freedom robot having redundant degrees of freedom, the other arm is used. It is necessary to give an instruction regarding the seventh degree of freedom using another means such as a push button or a lever operated by the user.

Japanese Patent Application Laid-Open No. 5-345291 discloses that the elbow position of the slave arm can be freely selected when controlling the position of the hand with the master arm. There is disclosed a seven-degree-of-freedom robot in which interference avoidance is performed when there is a possibility that the robot will interfere with an area where the robot has interfered. However, in the seven-degree-of-freedom robot disclosed in the above publication, the controller of the slave arm determines the elbow position regardless of the master arm, and does not reflect the intention of the operator in the redundant degree of freedom. Was.

[0005]

Accordingly, an object of the present invention is to provide a master arm which can reflect not only the position and orientation of the operator's hand but also the movement of the elbow. The purpose is to allow the operator to control all degrees of freedom of the slave arm with only one arm.

[0006]

In order to solve the above-mentioned problems, a master arm device according to the present invention has an elbow in which three axes at a shoulder intersect at approximately one point and three axes at a wrist intersect at approximately one point. A seven-degree-of-freedom master arm, comprising: an elbow sensor for detecting the position of the operator's elbow on the elbow; and a driving device for driving the elbow, and performing follow-up control of the elbow. I do.

In the master arm device of the present invention, the three axes intersect at one point at the shoulder and the three axes intersect at one point at the wrist, and each has a joint function equivalent to a ball joint. The movement of the elbow that is responsible for the freedom
It can be represented by rotation about a straight line connecting two axis intersections of a plane triangle formed by the axis intersection of the shoulder, the axis intersection of the wrist, and the elbow. The angle of rotation of this plane triangle is called the elbow angle. In the present invention, the elbow of the master arm is provided with a sensor for detecting the movement of the elbow of the pilot, and a device for driving the elbow is provided, and the elbow of the master arm is moved following the movement of the pilot. Can be done. Therefore, when the slave arm is likely to interfere with an external environment object, if the elbow is moved so as not to collide according to the judgment of the pilot, the master arm device controls the slave manipulator using the position information of the elbow to avoid the interference. Can be.

In the master arm device of the present invention, all degrees of freedom of the seven-degree-of-freedom manipulator can be controlled with only one of the arms of the operator. In addition, even when the two arms of the operator must control the arms of the manipulator, the position of the elbow can be controlled in addition to the position and orientation of the hand. Also, for example, when the forearm of the manipulator is likely to interfere with the work table on which the work object is mounted, the elbow can be moved horizontally, increasing the degree of freedom in the arrangement of the robot, making it possible to work even in a narrow space. There are advantages such as being able to.

[0009] Further, each axis of the master arm may be used as a drive axis, and the force detected by the slave arm may be presented to the operator. Further, the direction of the axis of rotation of the first axis of the master arm is substantially matched with the direction of gravity, the second axis is a drive axis orthogonal to the first axis and follows the movement of the elbow, and the rotation of the third and fourth axes The axes may be parallel to each other, and the counterweight of the fourth axis may be disposed on the rotation axis of the third axis, and the counterweight may be linked to the fourth axis via a parallel link mechanism. Preferably, the elbow sensor is provided on the link of the master arm and detects a direction in which the operator's arm moves relative to the link. Note that the elbow sensor may be one in which a plurality of photoelectric switches are arranged. With such a simple configuration of the elbow sensor, the control algorithm can be simplified, and the sensor unit and the control unit can be configured at extremely low cost.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings. FIG. 1 is a shaft arrangement diagram for explaining the configuration of one embodiment of the master arm device of the present invention, FIG. 2 is an explanatory diagram showing one example of an elbow sensor used in this embodiment, and FIG. 3 is another example of the elbow sensor. FIG. 4 is a shaft arrangement diagram illustrating an example of the arrangement of a counterbalance used in the present embodiment, FIG. 5 is a configuration diagram of a fourth axis counterbalance,
6 is a side view of the master arm device of the present embodiment, FIG. 7 is a plan view of the master arm device of the present embodiment, FIG. 8 is a drawing showing the attitude of a pilot in the master arm device of the present embodiment, and FIG. It is a block diagram showing the control device of the master slave manipulator device using this example.

The master arm device of this embodiment is for operating a seven-degree-of-freedom slave arm of a master-slave manipulator. The master arm has a link mechanism with seven degrees of freedom. When the operator grasps the wrist of the master arm and changes the position and orientation of the wrist, the position and orientation of the wrist can be determined by the rotation angle of the shaft provided from the shoulder to the wrist, and the information is used as a manipulator To control the slave arm to follow the movement of the master arm. Since only six degrees of freedom can be defined only by the position and orientation of the wrist of the slave arm, the remaining one degree of freedom is determined by the inclination of the arm connected to the elbow.

The shoulder and wrist of a person can be approximated to a spherical joint such as a ball joint where three rotation axes intersect at one point. The position of the elbow connected by the upper arm and the forearm with respect to the shoulder and the wrist is Once the positions of the shoulder and the wrist are determined, the rotation angle around the line connecting the shoulder and the wrist, that is, the elbow angle can be designated. It is convenient for handling that the elbow angle is indicated by a rotation angle measured from an appropriate reference position such as a vertical plane. In the master arm device of the present embodiment, three rotation axes are provided on the shoulder so that the axes intersect at one point, and three wrists are provided on the wrist in order to make the master arm perform the same movement as a human arm. The two rotation axes are provided so that the axes intersect at one point, and the upper arm link attached to the shoulder and the forearm link attached to the wrist are joined by a rotation axis such that both links bend in a plane to form an elbow I have.

The seven rotating shafts of the master arm in this embodiment are arranged as shown in FIG. Shoulder first
The rotating shaft 1 has a shaft in the direction of gravity and is supported by a fixed member. Further, a second rotating shaft 2 is connected to a rotating portion of the first rotating shaft 1 via a first link. The second rotation axis 2 has an axis in the horizontal direction, and the axis intersects the axis of the first rotation axis 1. The third rotating shaft 3 is connected to a rotating portion of the second rotating shaft 2 via a second link 8. The axis of the third rotating shaft 3 is the second
The axis of rotation 2 is substantially orthogonal to the axis of rotation,
It is arranged so as to pass through the intersection of the rotating shaft 2.

With the above configuration, the shoulder of the master arm can perform a movement equivalent to a ball joint centering on the intersection of the rotation axes. Needless to say, the arrangement of the first to third rotating shafts may be loose enough to achieve mechanical performance. The second link 8 has a slight length so that the operator's shoulder can be accommodated near the shoulder of the master arm.

The third rotating shaft 3 has a third arm serving as an upper arm.
A link 9 is attached, and a fourth rotating shaft 4 is provided at a tip of the third link 9. The axis of the fourth rotation shaft 4 is provided in parallel with the axis of the third rotation shaft 3. A fourth link 10 serving as a forearm is attached to the rotating portion of the fourth rotating shaft 4, and a fifth rotating shaft 5, which is the first rotating shaft in the wrist, is provided at the tip of the fourth link 10 in parallel with the fourth rotating shaft 4. Is provided.

The fifth rotating shaft 5 has a sixth link through a fifth link.
The rotating shaft 6 is connected, and the sixth rotating shaft 6 is connected to a seventh rotating shaft 7. The fifth rotation shaft 5, the sixth rotation shaft 6, and the seventh rotation shaft 7 are disposed so as to intersect at substantially one point, forming a three-degree-of-freedom joint of the wrist.

In the master arm device of this embodiment, an elbow sensor 11 for detecting the movement of the elbow of the operator is attached to the fourth link 10 corresponding to the forearm. Since the elbow sensor 11 only needs to detect the direction in which the forearm 31 of the operator 30 moves relative to the fourth link 10, a plurality of photoelectric switches as shown in FIG. 2 may be used. In the figure, four photoelectric switches are used, and these are arranged vertically to the movement of the arm. When the arm 31 is at an appropriate position, the two inner photoelectric switches detect the arm,
When the arm 31 moves in the direction approaching the fourth link 10, the photoelectric switch on the left side in the figure outputs a detection signal, and when the arm 31 moves in the direction away from the fourth link, the photoelectric switch on the right side in the figure operates. Detect movement. The elbow sensor 11 may be mounted anywhere on the fourth link 10, but is preferably determined in consideration of detection sensitivity and the like.

FIG. 3 is a drawing showing another example of an elbow sensor used in the present invention. The elbow sensor shown in FIG. 3 uses a micro linear scale. The linear scale main body 12 is fixed to the fourth link 10 of the master arm, and the end of the scale is tied to the band 13 wrapped around the forearm 31 of the pilot 30. Thus, the distance between the fourth link 10 and the forearm 31 of the pilot is measured. By adjusting the distance between them to be constant, the master arm can follow the operator's arm.

The second rotating shaft 2 is provided with a drive motor 14 that rotates in accordance with the measurement signal of the elbow sensor 11. When the driver's elbow is lifted outward, the drive motor 14 spreads the upper arm link 9 outward, and when the driver's elbow is lowered, the upper arm link 9 is also contracted inward. Therefore, the follow-up control of the elbow can be performed by moving the master arm so that the operator's elbow is always located at the center of the photoelectric switch group of the elbow sensor 11.

The master arm device is provided with a pair of left and right master arms having the above configuration, and can operate a dual-arm robot. When operating the slave arm by the master arm device of the present embodiment, the operator gets on the device and grips the joysticks at the wrists of the left and right master arms to guide the position and orientation of the wrist as desired.

Then, the master arm device calculates the position and posture of the wrist by detecting the rotation angle with encoders provided on each rotation shaft of the master arm, and transmits the calculated position and posture to the control device of the slave arm. This makes it possible to transmit information of six degrees of freedom of the movement of the operator's hand and one degree of freedom of the elbow position to the slave arm. Note that the position and orientation of the slave arm is instructed so that the difference between the operating force of the operator operating the master arm and the reaction force received by the slave arm from the work is eliminated. It may not work.

The slave arm control device performs inverse kinematics calculation based on the information on the position and orientation of the wrist of the master arm and the elbow angle, calculates the amount of rotation of each axis of the slave arm, and performs servo control. Thus, the position and orientation of the wrist of the slave arm can be determined as instructed by the operator. Furthermore, since the movement of the elbow of the pilot is detected and the elbow of the master arm is made to follow, when the arm or elbow of the slave arm is likely to interfere with surrounding objects, if the pilot moves the elbow, The elbow of the slave arm follows and moves through the movement of the master arm, so that interference can be avoided.

In order to make the movement of the elbow of the master arm correspond to the elbow of the pilot, the elbow angle may be set to the same value. In the master arm device of the present embodiment, only the second rotation shaft 2 of the master arm actively moves to adjust the opening angle of the upper arm link 9 in response to the movement of the elbow of the operator.
Since the reference axis of the elbow angle changes according to the movement of the hand, the opening angle of the upper arm link 9 does not necessarily become the elbow angle.
However, the difference between the two can be absorbed by another passive axis of rotation following the operator's arm. The second rotation axis 2 and the other rotation axes change according to the movement of the driver's arm, and based on the rotation angles of the respective rotation axes obtained as a result of the predetermined state, the inverse kinematics calculation is performed and the slave arm Controlling each joint causes the elbow to move according to the operator's intention.

Since the link mechanism of the master arm is ruggedly configured to have an appropriate strength, the weight becomes large for the operator to operate as it is, and it is difficult to freely move the link mechanism. In order to solve this difficulty, the master arm device of the present embodiment can arrange a counter balance as shown in FIG. Note that, since the parts smaller than the fourth link 10 are smaller and the role of the counterbalance is relatively smaller, the display in FIG. 4 is omitted. The counter balance may be attached to each rotating shaft. However, since the counter balance increases the weight of the entire mechanism and increases the inertial force, it is not preferable to use many heavy counterweights.

In a certain shaft configuration, if counterweights are arranged on all the rotating shafts, the counterweight to be provided on the first rotating shaft, which must receive all the weights from the base of the arm to the hand, is the largest. Become. In this embodiment, the counterweight is omitted by arranging the first rotating shaft 1 in the direction of gravity. A drive motor 14 for driving the upper arm in accordance with the elbow angle is provided on the second rotating shaft 2 where the weight of the counter weight should be the second largest.
And the counter weight was omitted. The third rotating shaft 3 is provided with a first counterweight 15 for appropriately canceling the moment on the hand side of the third link 9.

Next, the third rotating shaft 3 and the fourth rotating shaft 4 are arranged so that the rotating shafts are parallel to each other, and a parallel link 17 is formed between the third rotating shaft 3 and the fourth rotating shaft 4. Thus, the second counterweight 16 for the fourth rotating shaft 4 is disposed around the third rotating shaft 3. By arranging the second counterweight 16 around the third rotation axis, the moment around the third axis due to the weight of the second counterweight is reduced, and the weight of the first counterweight to be balanced with it can be reduced. Accordingly, the load on the arm of the pilot 30 is significantly reduced as compared with a case where the operation is performed symmetrically with respect to the axis of the fourth rotation shaft 4 so as to be performed normally, so that the steering is more easily performed. Become.

FIG. 5 is a mechanism diagram showing an example of a parallel link provided to provide a counter weight for the fourth rotating shaft on the third rotating shaft. A first pulley is fixed to the rotation shaft of the fourth rotation shaft 4, and a second pulley having the same diameter as the first pulley is rotatably supported on the third rotation shaft 3. A second counterweight is fixed to the second pulley. Metal bands 18 and 19 are passed between the first pulley and the second pulley, and each end is fixed to the pulley by a fixing bolt 21. A tension controller 20 is set between the first pulley and the second pulley, and the metal belts 18, 19
So that there is no slack.

When the operator moves the hand holding the joystick 22 provided on the wrist, the fourth link 10 is moved to the fourth link.
When it rotates around the rotation axis, this rotation
The second counter weight 16 is transmitted to the second pulley via the first and second pulleys 8 and 19. The second counterweight 16 mainly cancels the moment of the link mechanism from the fourth link 10 to the hand. Further, since the weight of the first counterweight 15 is reduced by disposing the second counterweight 16 near the third axis, the burden on the operator's arm is small. In addition, the illustrated parallel link mechanism has a small number of additional components and can be formed so as to fit within the width of the third link 9, so that the interference area between the operator and the mechanism is reduced. can do.

FIGS. 6 and 7 are an elevation view and a plan view of the master arm device of the present embodiment. The first to third axes intersect at the rotation center point of the shoulder, and the fifth to seventh axes intersect at the hand position. The fourth shaft connects the upper arm link 9 and the forearm link 10 rotatably. The third to fifth axes are arranged in parallel with each other. The rotating portion of the third shaft projects outward from the center of rotation of the shoulder by the distance of the shoulder link 8. In addition, the distance from the rotating portion of the fifth shaft to the rotation center of the wrist portion is configured to be the same distance as the shoulder link 8 by a mechanism interposed therebetween. Drive motor 1 on the second axis
4 is connected to adjust the opening angle of the elbow of the link 9.

A first counterweight 15 and a second counterweight 16 are mounted around the third axis. The first counterweight 15 is provided at a point symmetrical position with respect to the third arm so as to substantially cancel the moment of the entire hand portion below the upper arm link 9. The second counterweight 16 has a function of interlocking with the forearm link 10 by means of a parallel link mechanism provided in the upper arm link 9 to substantially cancel the moment of the mechanical portion below the forearm link 10. Also, forearm link 1
0 is provided with an elbow sensor 11 for detecting the movement of the operator's arm.

FIG. 8 schematically shows a state in which the operator operates while riding on the master arm device of the present embodiment shown in FIGS. 6 and 7. The master arm device is fixed by fixing the fixing portion of the first rotation shaft to the gantry 23. When the pilot 30 gets on the apparatus and grips the joystick of the master arm, the center of rotation of the pilot's shoulder and the center of rotation of the master arm are sufficiently close, and the upper arm link and the forearm link are connected to the operator's arm 31. Are arranged along
The movement of the driver's arm 31 is detected by the elbow sensor 11. When the pilot moves his elbow without changing his position,
Since the straight line connecting the shoulder rotation center and the wrist rotation center almost coincides with the straight line connecting the pilot's shoulder and the wrist, the correspondence between the elbow angles is simplified.

Further, it is also possible to arrange a motor on each of the first axis to the seventh axis so that the force can be presented. The force presentation is a function of presenting a force generated when a slave arm is provided with a force sensor and coming into contact with a workpiece to a driver. In addition, a force sensor is provided on a grip portion at a wrist portion of the master arm to detect an operation force exerted by the pilot's hand on the master arm and generate a force according to the operation force between the slave arm and the work. Can also.

FIG. 9 is a block diagram showing a control mechanism of a master-slave manipulator device using the master arm device of this embodiment. The upper half of the drawing represents the drive control unit of the master arm, and the lower half represents the drive control unit of the slave arm. The elbow angle command value is calculated by the elbow sensor 41, the direction calculation unit 42 of the operator's elbow position, and the current position calculation unit 4 of the elbow angle.
3, and calculated by the adder 44. Elbow sensor 41
Detects a change in the relative position between the arm of the pilot and the arm link of the master arm, and inputs a detection signal to the direction calculation unit 42. The direction calculation unit 42 detects the movement direction of the elbow position of the pilot and the master arm. Calculate the amount of movement required for the elbow to follow. The elbow angle command value is calculated by integrating the movement amount by the integrator 44.

The elbow angle command value is sent to an inverse kinematics calculation section 45 of the master arm, where the amount of rotation of each axis is calculated. To follow the movement of the pilot's arm. The elbow angle command value is also sent to the inverse kinematics calculation unit 52 of the slave arm, and drives each axis of the slave arm via each axis servo control unit 53 based on the calculated drive amount. To follow the pilot's arm.

On the other hand, a force sensor 47 provided on the master arm measures the operating force of the driver, and a force sensor 48 provided on the slave arm measures the reaction force of the work. The subtractor 49 calculates the difference between the operation force of the operator and the reaction force of the work, and the integrator 50 integrates the difference. The arm position initial value of the slave arm is calculated from the rotation value of each axis, and the calculated value is added to the output of the integrator 50 by the adder 51. Adder 51
Is a hand position command value that changes the hand position in a direction in which the operator's force matches the work reaction force, and when the two match, the hand position command value is maintained. The hand position command value is sent to the inverse kinematics calculation section 52 of the slave arm, and each axis servo control section 53 drives each axis of the slave arm based on the calculated drive amount, and controls the slave arm to move the arm of the operator. To follow. Further, it is sent to the inverse kinematics calculation section 45 of the master arm, and based on it, the drive motor is driven by the servo control section 46 so that the master arm follows the slave arm and presents a force to the operator.

[0036]

As described above, the master arm device of the present invention is applicable to a slave arm having seven degrees of freedom.
Since it becomes possible to teach not only the position of the hand but also the position of the elbow, for example, for a master-slave manipulator device in a dual-arm robot,
The operator can move the elbow while observing the situation at the site to avoid obstacles in the slave arm.

[Brief description of the drawings]

FIG. 1 is a shaft arrangement diagram for explaining a configuration of an embodiment of a master arm device of the present invention.

FIG. 2 is an explanatory diagram illustrating an example of an elbow sensor used in the present embodiment.

FIG. 3 is an explanatory diagram showing another example of an elbow sensor used in the present embodiment.

FIG. 4 is an axial arrangement diagram illustrating an arrangement of a counter balance used in the present embodiment.

FIG. 5 is a configuration diagram of a fourth axis counterbalance used in the present embodiment.

FIG. 6 is a side view of the master arm device of the present embodiment.

FIG. 7 is a plan view of the master arm device of the present embodiment.

FIG. 8 is a drawing showing a posture of a pilot in the master arm device of the present embodiment.

FIG. 9 is a block diagram illustrating a control device of a master-slave manipulator device using the present embodiment.

[Explanation of symbols]

 1, 2, 3, 4, 5, 6, 7 Rotation axis 8, 9, 10 Link 11 Elbow sensor 12 Linear scale body 13 Band for linear scale 14 Drive motor 15, 16 Counter weight 17 Parallel link 18, 19 Metal belt 20 Tension controller 21 Fixing bolt 22 Joystick 23 Mount 30 Pilot 31 Pilot's forearm

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshiyuki Idoko 118 Futatsuka Noda City, Chiba Prefecture Kawasaki Heavy Industries Noda Plant F-term (reference) 3F059 AA00 AA01 BA02 CA06 DA05 DA09 DC04 DC08 DD01 DD12 DE02 EA01 EA05 FA01 FA03 FA10 FB01 FB13 FB17 FB21 FB29 FC02 FC03 FC06 FC13 FC14 3F060 AA00 AA01 BA06 EB11 EB14 EC13 FA06 GA05 GA13 GB02 GB06 GB07 GB11 GC01 GD12 GD14 HA22 HA35

Claims (5)

[Claims] 1. A seven-degree-of-freedom master arm having three elbows where the three axes intersect at approximately one point at the shoulder and the three axes intersect at approximately one point at the wrist. A master arm device comprising: an elbow sensor for detecting; and a driving device for driving the elbow, so that the elbow follows an elbow position of a pilot. 2. The master arm device according to claim 1, wherein a drive device is provided on a rotation shaft corresponding to each degree of freedom of the master arm to perform force presentation. 3. A direction of a rotation axis of a first axis of the master arm substantially coincides with a direction of gravity, and a second axis is a drive axis orthogonal to the first axis and following the movement of an elbow. The rotation axis of the fourth axis is parallel to the rotation axis of the third axis.
The master arm device according to claim 1, wherein a counter weight of the shaft is arranged, and the counter weight is linked with the fourth shaft via a parallel link mechanism. 4. The system according to claim 1, wherein the elbow sensor is provided on a link of the master arm and detects a direction in which a driver's arm moves relative to the link. The master arm device according to any one of the above. 5. The master arm device according to claim 4, wherein said elbow sensor includes a plurality of photoelectric switches arranged side by side.